Apparatus and System For Swing Adsorption Processes

ABSTRACT

Provided are apparatus and systems for performing a swing adsorption process. This swing adsorption process may involve performing a startup mode process prior to beginning a normal operation mode process to remove contaminants from a gaseous feed stream. The startup mode process may be utilized for swing adsorption processes, such as TSA and/or PSA, which are utilized to remove one or more contaminants from a gaseous feed stream.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional of U.S. patent application Ser. No. 15/496,510,filed Apr. 25, 2017, which claims the benefit of U.S. Provisional PatentApplication 62/343,424, filed May 31, 2016, entitled APPARATUS ANDSYSTEM FOR SWING ADSORPTION PROCESSES, the entirety of which isincorporated by reference herein.

FIELD

The present techniques relate to a method and system associated withswing adsorption processes used in conditioning streams for downstreamprocessing. In particular, the method and system involve a startup modeprocess for a swing adsorption process, which is further utilized forstarting up the downstream process.

BACKGROUND

Gas separation is useful in many industries and can typically beaccomplished by flowing a mixture of gases over an adsorbent materialthat preferentially adsorbs one or more gas components while notadsorbing one or more other gas components. The non-adsorbed componentsare recovered as a separate product.

One particular type of gas separation technology is swing adsorption,such as temperature swing adsorption (TSA), pressure swing adsorption(PSA), partial pressure swing adsorption (PPSA), rapid cycle temperatureswing adsorption (RCTSA), rapid cycle pressure swing adsorption (RCPSA),rapid cycle partial pressure swing adsorption (RCPPSA), and not limitedto but also combinations of the fore mentioned processes, such aspressure and temperature swing adsorption. As an example, PSA processesrely on the phenomenon of gases being more readily adsorbed within thepore structure or free volume of an adsorbent material when the gas isunder pressure. That is, the higher the gas pressure, the greater theamount of readily-adsorbed gas adsorbed. When the pressure is reduced,the adsorbed component is released, or desorbed from the adsorbentmaterial.

The swing adsorption processes (e.g., PSA and/or TSA) may be used toseparate gases of a gas mixture because different gases tend to fill themicropore of the adsorbent material to different extents. For example,if a gas mixture, such as natural gas, is passed under pressure througha vessel containing an adsorbent material that is more selective towardscarbon dioxide than it is for methane, at least a portion of the carbondioxide is selectively adsorbed by the adsorbent material, and the gasexiting the vessel is enriched in methane. When the adsorbent materialreaches the end of its capacity to adsorb carbon dioxide, it isregenerated by reducing the pressure, thereby releasing the adsorbedcarbon dioxide. Then, the adsorbent material is typically purged andrepressurized prior to starting another adsorption cycle.

The swing adsorption processes typically involve adsorbent bed units,which include adsorbent beds disposed within a housing and configured tomaintain fluids at various pressures for different steps in a cyclewithin the unit. These adsorbent bed units utilize different packingmaterial in the bed structures. For example, the adsorbent bed unitsutilize checker brick, pebble beds or other available packing. As anenhancement, some adsorbent bed units may utilize engineered packingwithin the bed structure. The engineered packing may include a materialprovided in a specific configuration, such as a honeycomb, ceramic formsor the like.

Further, various adsorbent bed units may be coupled together withconduits and valves to manage the flow of fluids through the cycle.Orchestrating these adsorbent bed units involves coordinating the stepsin the cycle for each of the adsorbent bed units with other adsorbentbed units in the system. A complete cycle can vary from seconds tominutes as it transfers a plurality of gaseous streams through one ormore of the adsorbent bed units.

As may be appreciated, the removal of contaminants may result in theprocess operating in different modes, such as a startup mode and anormal operation mode. The startup mode may be utilized to prepare theequipment (e.g., the adsorbent bed and various stream) for the normaloperation mode. The normal operation mode may be utilized when theprocess is receiving various streams, such as the gaseous feed stream,and removing contaminants from the gaseous feed stream to provide aproduct stream, which may be referred to as steady state. For example,the conventional processes may operate in normal operation mode to treathydrocarbon containing streams containing water (H₂O) or carbon dioxide(CO₂) to prepare the stream for downstream processing, such as naturalgas liquid recovery (NGL) or liquefied natural gas (LNG) processing. Thenormal operation modes may be different for each of the respectivedownstream processes based on the respective specifications that areinvolved for normal operational mode. For example, a typical LNGspecification requires the CO₂ content to be less than 50 parts permillion molar (ppm).

During the startup mode, the cycle may be different than the cycleutilized for normal operation mode. Conventional systems may utilize asingle heating step to regenerate the adsorbent material with hightemperatures to remove any contaminants as the startup mode cycle. Forexample, a startup process involving a mole sieve unit may includeheating the bed to temperatures in excess of 550° F.

Unfortunately, conventional startup mode processes have certainlimitations. For example, the process in startup mode may involve merelyheating the adsorbent material to high temperatures. The heating of theadsorbent material to high temperatures in the conventional approachestypically rely upon dedicated high-temperature startup heaters. Theseheaters are expensive, involve large capital expenditure and highoperational costs. In addition, these heaters increase the weight andfootprint of the facility. Further, the cycle time is typically longerthan necessary to remove contaminants to ensure sufficient time isprovided for downstream equipment to begin operations. In addition, thetemperature that the adsorbent material are exposed to may lessen theoperational life of the adsorbent material and may lessen the efficiencyof the adsorbent material.

Accordingly, there remains a need in the industry for apparatus,methods, and systems that provided enhancements to the start-upprocesses associated with hydrocarbon recovery processes. In particular,a need exists for enhancements to startup mode processes for rapid cycleswing adsorption processes.

SUMMARY OF THE INVENTION

In one embodiment, the present techniques describe a process forremoving contaminants from a gaseous feed stream with a swing adsorptionprocess. The process comprises passing a gaseous feed stream to a swingadsorption process that comprises a plurality of adsorbent bed units,each of the adsorbent bed units performs a swing adsorption cycle thatincludes an adsorption step and a regeneration step; wherein the swingadsorption cycle comprises: performing a first bed adsorption step for afirst adsorbent bed unit of the plurality of adsorbent bed units thatcomprises passing a gaseous feed stream through the first adsorbent bedunit having a first adsorbent bed to separate one or more contaminantsfrom the gaseous feed stream to form a first product stream; andperforming a second bed regeneration step for a second adsorbent bedunit of the plurality of adsorbent bed units that comprises passing atleast a portion of the first product stream through the second adsorbentbed unit having a second adsorbent bed to separate one or morecontaminants from the second adsorbent bed to form a first purge productstream.

Further, in another embodiment, the present techniques describe aprocess for removing contaminants from a gaseous feed stream with aswing adsorption process. The process comprises: passing a gaseous feedstream to a swing adsorption process that comprises a plurality ofadsorbent bed units, each of the adsorbent bed units performs a swingadsorption cycle that includes an adsorption step and a regenerationstep; wherein the swing adsorption cycle comprises: performing aadsorption step for one of the plurality of adsorbent bed units thatcomprises passing a portion of the gaseous feed stream through the oneof the plurality of adsorbent bed units to remove one or morecontaminants from the gaseous feed stream and conduct away a productstream; and performing a regeneration step for the one of the pluralityof adsorbent bed units that comprises passing at least a portion of aproduct stream from another of the plurality of adsorbent bed unitsthrough the one of the plurality of adsorbent bed units to remove one ormore contaminants from the one of the plurality of adsorbent bed unitsand conduct away a purge product stream.

In yet another embodiment, a cyclical swing adsorption system isdescribed. The system includes: a plurality of manifolds, wherein theplurality of manifolds comprise a feed manifold configured to pass afeed stream to the plurality of adsorbent bed units during an adsorptionstep, a product manifold configured to pass a product stream from theplurality of adsorbent bed units during the adsorption step, a purgemanifold configured to pass a purge stream to the plurality of adsorbentbed units during a regeneration step, a purge product manifoldconfigured to pass a purge product stream from the plurality ofadsorbent bed units during the regeneration step, each manifold of theplurality of manifolds is associated with one swing adsorption processstep of a plurality of swing adsorption process steps; a plurality ofadsorbent bed units coupled to the plurality of manifolds, each of theadsorbent bed units comprising: a housing; an adsorbent materialdisposed within the housing; a plurality of valves, wherein at least oneof the plurality of valves is associated with one of the plurality ofmanifolds and is configured to manage fluid flow along a flow pathextending between the respective manifold and the adsorbent material; astartup mode bypass valve in fluid communication with purge manifold andthe product manifold and configured to provide a flow passage betweenthe product manifold and the purge manifold in a startup mode positionand configured to block the flow passage between the product manifoldand the purge manifold in a normal operation mode position.

In certain embodiments, the process and system may include someadditional variations. The process may include: determining whether thefirst product stream is within a specification for a contaminant; if thefirst product stream is within the specification, passing at least aportion of the first product stream to a downstream process; if thefirst product stream is not within the specification, performing aregeneration step for the first adsorbent bed unit that comprisespassing a portion of a second product stream through the first adsorbentbed unit to separate one or more contaminants from the first adsorbentbed to form a second purge product stream, wherein the second productstream is provided from another of the plurality of adsorbent bed units;and repeating the adsorbent step for the first adsorbent bed unit. Also,the process may include mixing a slip stream (e.g., an overhead stream)from the downstream process with the at least a portion of the firstproduct stream prior to performing the second bed regeneration step;and/or adjusting the amount of at least a portion of the first productstream utilized in the second bed regeneration step based on the amountof slip stream from the downstream process.

In other embodiments, the process and system may include additionalfeatures. The plurality of valves may comprise one or more poppetvalves; the plurality of manifolds and/or the plurality of adsorbent bedunits may be configured to operate at pressures between 0.1 bar absolute(bara) and 100 bara; and/or wherein the plurality of manifolds mayfurther comprise a blowdown manifold configured to pass a blowdownstream from the plurality of adsorbent bed units during a blowdown step.The cyclical swing adsorption system may further comprise a heating unitdisposed upstream of the purge manifold and downstream of the productmanifold, wherein the heating unit may be configured to heat the productstream to a temperature in the range between 450° F. and the gaseousfeed stream temperature; a separating unit may be disposed upstream ofthe purge manifold and downstream of the heating unit, wherein theseparating unit may be configured to lessen the pressure of the productstream to a pressure in the range between 0.1 bar absolute (bara) and100 bara, which is lower than the pressure within the product stream orwhich may lower the pressure by at least 10%, by at least 20% or atleast 30% relative to the pressure of the product stream exiting thefirst adsorbent bed; a conditioning unit disposed downstream of thepurge product manifold and upstream of the feed manifold, wherein theconditioning unit may be configured to remove one or more contaminantsfrom the purge product stream; a liquefied natural gas process unit influid communication with the adsorbent bed unit and may be configured toreceive the product stream and separate the product stream into a finalproduct stream and a flash fuel stream, wherein the flash fuel stream ispassed to the purge manifold; and/or a cryogenic natural gas liquidrecovery (NGL) process unit in fluid communication with the adsorbentbed unit and configured to receive the product stream and separate theproduct stream into a final product stream and a residue gas stream,wherein the residue gas stream is passed to the purge manifold.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other advantages of the present disclosure may becomeapparent upon reviewing the following detailed description and drawingsof non-limiting examples of embodiments.

FIG. 1 is a three-dimensional diagram of the swing adsorption systemwith six adsorbent bed units and interconnecting piping in accordancewith an embodiment of the present techniques.

FIG. 2 is a diagram of a portion of an adsorbent bed unit havingassociated valve assemblies and manifolds in accordance with anembodiment of the present techniques.

FIG. 3 is an exemplary flow chart for performing an external startupmode of a swing adsorption process in accordance with an embodiment ofthe present techniques.

FIG. 4 is an exemplary flow chart for performing a recycle startup modeof a swing adsorption process in accordance with an embodiment of thepresent techniques.

FIG. 5 is an exemplary diagram of a startup mode step in accordance withan embodiment of the present techniques.

FIGS. 6A and 6B are exemplary diagrams associated with another startupmode step in accordance with an embodiment of the present techniques.

FIG. 7 is an exemplary diagram associated with yet another startup modestep in accordance with an embodiment of the present techniques.

FIG. 8 is an exemplary diagram associated with the recycle startup modestep in accordance with an embodiment of the present techniques.

FIGS. 9A and 9B are exemplary diagrams associated with the recyclestartup mode step in accordance with an embodiment of the presenttechniques.

FIG. 10 is an exemplary diagram associated with another startup modestep in accordance with an embodiment of the present techniques.

FIG. 11 is an exemplary diagram associated with still another startupmode step in accordance with an embodiment of the present techniques.

FIG. 12 is an exemplary diagram associated with normal operation mode.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise explained, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which this disclosure pertains. The singular terms“a,” “an,” and “the” include plural referents unless the context clearlyindicates otherwise. Similarly, the word “or” is intended to include“and” unless the context clearly indicates otherwise. The term“includes” means “comprises.” All patents and publications mentionedherein are incorporated by reference in their entirety, unless otherwiseindicated. In case of conflict as to the meaning of a term or phrase,the present specification, including explanations of terms, control.Directional terms, such as “upper,” “lower,” “top,” “bottom,” “front,”“back,” “vertical,” and “horizontal,” are used herein to express andclarify the relationship between various elements. It should beunderstood that such terms do not denote absolute orientation (e.g., a“vertical” component can become horizontal by rotating the device). Thematerials, methods, and examples recited herein are illustrative onlyand not intended to be limiting.

As used herein, “stream” refers to fluid (e.g., solids, liquid and/orgas) being conducted through various equipment. The equipment mayinclude conduits, vessels, manifolds, units or other suitable devices.

As used herein, “conduit” refers to a tubular member forming a channelthrough which something is conveyed. The conduit may include one or moreof a pipe, a manifold, a tube or the like.

The provided processes, apparatus, and systems of the present techniquesmay be used in swing adsorption processes that remove contaminants (CO₂,H₂O, and H₂S) from feed streams, such as hydrocarbon containing streams.As may be appreciated and as noted above, the hydrocarbon containingfeed streams may have different compositions. For example, the gaseousfeed stream may be a hydrocarbon containing stream having greater thanone volume percent hydrocarbons based on the total volume of the feedstream. As another example, the hydrocarbon feed streams vary widely inamount of acid gas, such as from several parts per million acid gas to90 volume percent (vol. %) acid gas. Non-limiting examples of acid gasconcentrations from exemplary gas reserves sources includeconcentrations of approximately: (a) 4 ppm H₂S, 2 vol. % CO₂, 100 ppmH₂O (b) 4 ppm H₂S, 0.5 vol. % CO₂, 200 ppm H₂O (c) 1 vol. % H₂S, 2 vol.% CO₂, 150 ppm H₂O, (d) 4 ppm H₂S, 2 vol. % CO₂, 500 ppm H₂O, and (e) 1vol. % H₂S, 5 vol. % CO₂, 500 ppm H₂O. Further, in certain applicationsthe hydrocarbon containing stream may include predominately hydrocarbonswith specific amounts of CO₂ and/or water. For example, the hydrocarboncontaining stream may have greater than 0.00005 volume percent CO₂ basedon the total volume of the gaseous feed stream and less than 2 volumepercent CO₂ based on the total volume of the gaseous feed stream; orless than 10 volume percent CO₂ based on the total volume of the gaseousfeed stream. The processing of feed streams may be more problematic whencertain specifications have to be satisfied.

The removal of contaminants may be performed by swing adsorptionprocesses during normal operations to prepare the stream for furtherdownstream processing, such as NGL processing and/or LNG processing. Forexample, natural gas feed streams for liquefied natural gas (LNG)applications have stringent specifications on the CO₂ content to ensureagainst formation of solid CO₂ at cryogenic temperatures. The LNGspecifications may involve the CO₂ content to be less than or equal to50 ppm. Such specifications are not applied on natural gas streams inpipeline networks, which may involve the CO₂ content up to 2 vol. %based on the total volume of the gaseous feed stream. As such, for LNGfacilities that use the pipeline gas (e.g., natural gas) as the rawfeed, additional treating or processing steps are utilized to furtherpurify the stream. Further, the present techniques may be used to lowerthe water content of the stream to less than 0.1 ppm. Exemplary swingadsorption processes and configurations may include U.S. Patent Ser.Nos. 62/213,262; 62/213,267; 62/213,270; 62/213,273; 62/246,916;62/246,920; and 62/246,922, which are each incorporated by referenceherein.

The present techniques provide configurations and processes that areutilized to enhance the startup mode for the swing adsorption processand associated downstream processes. While the normal operation modeprocesses are described based on steady state operation, startup modeprocedures involve different cycles until normal operation mode isbegun. The present techniques describes different methods that may beutilized to transition the operation from startup mode to normaloperation mode. In startup mode, each of the adsorbent beds utilized inthe swing adsorption process is assumed to be in equilibrium withcontaminants. For dehydration applications, the contaminant is water(H₂O), while for carbon dioxide (CO₂) applications, the contaminant iseither H₂O (e.g., in equilibrium with atmosphere) or CO₂ (e.g., in caseof a shutdown). Accordingly, the startup mode is utilized to removecontaminants to prepare the adsorbent beds for normal operation mode. Inparticular, the startup mode sequence may be used for swing adsorptionprocesses (e.g., dehydration and low-level CO₂ removal) upstream orintegrated with NGL and LNG applications.

A first startup mode process may involve the use of an external mediumto remove one or more contaminants from the adsorbent beds. In theexternal startup mode, an external medium is used to remove one or morecontaminants from the adsorbent beds. The external medium may includethe use of an external gas stream that is circulated through theadsorbent beds to remove the one or more contaminants from the adsorbentbeds during a regeneration step (e.g., a purge step). The external gasstream may include nitrogen, dry methane or other non-reactive streamunder process operating conditions. For example, the external stream mayinclude predominately nitrogen or methane with less than 0.1 ppm ofwater, less than 1 ppm of water or less than 10 ppm of water.

For example, in dehydration applications, an external gas stream, suchas dry nitrogen (e.g., nitrogen stream having less than 0.1 ppm ofwater, less than 1 ppm of water or less than 10 ppm of water), may beused to remove water from the adsorbent beds during the startup mode.When the dry nitrogen stream is introduced into each of the adsorbentbeds, which is at equilibrium with ambient water, some of the watertransfers from the adsorbent material in the adsorbent bed to the drynitrogen stream. The startup mode sequence may involve providing feed tothe adsorbent bed during an adsorption step and using the externalstream to purge the adsorbent bed during a purge step. The startup modecycle may continue to use the dry nitrogen until a sufficient amount ofwater is removed from each of the adsorbent beds and a desired bedprofile is achieved for the adsorbent beds. Then, the resulting productstream from the adsorbent beds is within the desired specification(e.g., below the specific contaminant levels for the product stream). Inaddition, the startup mode may include maintaining the purge step withdry nitrogen to sufficient amounts of moisture, and then start thesequence described above. In such a configuration, the product streammay be within specification from the first cycle.

Once the product stream is within the desired specification, the productstream may be used in the startup mode process for the downstreamprocesses, such as a demethanizer or a liquefaction train. As thedownstream processes and units are being started, the adsorbent bedscontinue to regenerate using the external gas stream, such as the drynitrogen stream. Alternatively, a heated slip stream from the productside may also be used to regenerate the spent adsorbent beds. As thedownstream process begins producing a purge stream, this purge streammay be combined with the external gas stream and the amount of externalgas stream utilized in the purge step may be adjusted. Once thedownstream processes begin normal operations, the desired purge stream(e.g., within the desired specifications), such as a residue gas streamor fuel gas stream, is provided to the adsorbent bed as part of thenormal operation mode. At this point, the adsorbent bed regenerationstream is transitioned from nitrogen to the purge stream from thedownstream process.

To facilitate rapid regeneration and minimize the amount of dry nitrogenbeing utilized during the external startup mode, the operatingconditions may be adjusted to manage the removal of contaminants fromthe adsorbent bed. For example, the flow rate for the gaseous feedstream may be conducted within a flow rate range below the normaloperation mode flow ranges (e.g., flow rate at turndown). For example,the flow rates in startup mode may be at about 25% of the normaloperation mode flow rate, at about 50% of the normal operation mode flowrate, at about 75% of the normal operation mode flow rate, in a rangebetween 25% and 90% of the normal operation flow rate, in a rangebetween 50% and 90% of the normal operation flow rate, and in a rangebetween 75% and 90% of the normal operation flow rate. Further, theregeneration of the adsorbent bed may be conducted within a pressurerange near atmospheric pressure (e.g., in a pressure range betweenatmospheric pressure and fifty pounds per square inch gauge (psi) aboveatmospheric pressure) or may be within a pressure range near normaloperation mode pressures (e.g., in a pressure range between 75% ofnormal operation mode pressure and 125% of normal operation modepressure or at a pressure between atmospheric pressure and normaloperating pressure or a pressure close to feed pressure). As an example,the regeneration of the adsorbent bed may be conducted in a pressurerange from 300 pounds per square inch gauge (psi) to 650 psi. Also, thetemperature of the external medium stream may be provided within atemperature range from (e.g., in a temperature range between 20° Celsius(C) above atmospheric temperature and 150° Celsius (C) above atmospherictemperature). Also, the temperature of the external stream may be in arange between 350° F. and 550° F., in a range between 350° F. and 550°F. or in a range 450° F. and 550° F. in a range between 100° F. and 550°F., in a range between 150° F. and 450° F. or in a range 250° F. and350° F.

In the second startup mode process, the startup cycle may include anadsorption step and a regeneration step (e.g., purge step). In thisrecycle startup mode sequence, at least a portion of the product streamfrom a first adsorbent bed may be recycled to a second adsorbent bed asthe purge stream to progressively clean the adsorbent beds (e.g., lowerthe levels of contaminants in the adsorbent beds). Heat may be added tothis stream to increase the temperature and yield a stream that is lesssaturated in the contaminants than the feed stream. As the adsorbentbeds within a swing adsorption process may be performing different stepswithin the respective cycles, at least a portion of the product streamfrom an adsorbent bed in the adsorption step may be used as the purgestream for an adsorbent bed in the purge step. The resulting purgeproduct stream may be flared, recycled to be mixed with the feed streamafter a contaminant knockout (e.g., water knockout), and/or provided tofuel. The recycle startup mode process may involve gradually loweringthe levels of contaminants within the adsorbent beds until the levelthat satisfies a predetermined desired level for the adsorbent beds. Theat least a portion of the first product stream is greater than 5% of theproduct stream, greater than 50% of the product stream or greater than75% of the product stream.

As an example, the recycle startup mode process may be used to removewater from two or more adsorbent beds in the swing adsorption process.Initially, the adsorbent beds may be saturated with water at theoperating conditions. Then, a wet gas stream may be passed through thefirst adsorbent bed, which may result in water being removed from thewet gas steam. In this first cycle, the wet gas stream may not undergodehydration or may undergo minimal dehydration because the adsorbent bedis saturated and it does not adsorb any more moisture from the stream.Then, the resulting product stream, which is a partially dehydrated gasstream may be heated to a high temperature using a startup heater. Thetemperatures may be in a range between 100° F. and 550° F., in a rangebetween 150° F. and 450° F. or in a range 250° F. and 350° F. Thestartup heater may include a furnace, heat exchanger or other suitableheating unit. Next, the pressure of the heated stream may be lowered,resulting in a purge stream that is at a lower pressure and highertemperature than the partially dehydrated gas stream. This purge streamis used to purge a second or different adsorbent bed to remove a portionof the water within that adsorbent bed. In the second such cycle theadsorbent bed adsorbs some water resulting in a dryer product stream.The water removed from the stream is purged in the subsequent purge stepbecause the purge has more moisture removal capability than the previouscycle (e.g., it is dryer than before). This cycle is continued for acertain duration, after which the purged adsorbent bed is provided afeed stream and the cycle repeated. The recycle startup processprogressively purges each of the adsorbent beds and lessens the waterpresent within the respective adsorbent beds. With each successivecycle, the water content of the partially dehydrated gas decreases,eventually bringing the product stream from the respective adsorbent bedto the specification.

For a dehydration application, the sequence of the cycle for the startupmode may be configured to lessen flaring of gas or completely eliminateflaring of gas. The recycle sequence may be initiated at turndown. Thepurge pressure is selected such that the purge product is at the suctionpressure of the residue gas compressor. The residue gas compressor isthen operated to compress the purge product and recombine with the feedstream either upstream or downstream of a triethylene glycol (TEG) baseddehydration unit. Knockout drums may be necessary to remove the excesswater gathered from the purge step.

As a specific example, the recycle startup process may be used for acryogenic NGL recovery facility. The recycle startup process may includepassing wet gas to the absorbent units at turndown. Then, the recyclestartup process is utilized to clean the adsorbent beds. The process iscontinued until product stream is at specification and the desired waterprofile in the adsorbent bed is achieved. Next, the flow rate of the gasstream entering the adsorbent beds is increased for subsequent cycles.Then, a slip stream of the dry product stream is introduced to thecryogenic NGL recovery facility. The remaining product gas is used aspurge stream. As necessary, the purge inlet temperature may be adjustedto achieve the necessary purge to remove the water in the adsorbentbeds. The process may be similar to the external startup mode except apartially dehydrated purge stream is utilized instead of an externalstream. With the product stream from the adsorbent beds, the startupsequence for the cryogenic NGL recovery facility is initiated. Thiscryogenic NGL facility may perform the startup mode in a recycle modeusing the residue gas compressor to recycle the demethanizer columnoverhead product with the feed. Once the NGL recovery facility isapproaching specification, a portion of the demethanizer overheadproduct is mixed with the purge stream from the adsorbent beds in swingadsorption process to increase the flow rate. The heat from the startupheater may be reduced as necessary. Eventually, the overhead productstream from the demethanizer is introduced to the adsorbent beds as apurge stream for the respective cycles and the portion of the productstream from the adsorbent bed being used as the purge stream is lessenedand may be eliminated. The process eventually transitions to normaloperation mode, which is a steady state with the adsorbent beds purgeproduct gas being provided for sale.

Similarly, the above sequence may be used for the LNG process. However,a source of gas to compress the purge product to feed pressure may notbe available with the LNG process during startup mode. As such, some ofthe purge stream may have to be flared. For the CO₂ removal processes, asimilar recycle startup mode sequence may be used. Additionally, a loopheating step may be used to provide the necessary heat to the adsorbentbeds.

One or more variants to the procedure noted above may be used to reducethe startup time of the process. The first variant includes heatingadsorbent beds to reduce the amount of water in the adsorbent beds,which may be performed initially. In the heating step, the heated wetgas at low pressure is used as the purge stream for the absorbent bedsand removes a large amount of water already adsorbed in the adsorbentbeds. A second variant involves performing one or more blowdown steps inthe startup mode process to flare or rapidly decrease the partialpressure and reduce the amount of water adsorbed in the adsorbent beds.A third variant involves performing a purge step with dry nitrogen,which may be heated, if necessary, to dry the adsorbent beds.

The present techniques provide a startup mode process that may beutilized to initiate the normal operation mode process for a swingadsorption process, and specifically a rapid cycle adsorption process.The present techniques may include some additional equipment, such asone or more conduits and/or one or more manifolds that provide a fluidpath for the external gas stream, an external gas storage tank, aheating unit (furnace and/or heat exchanger), one or more blowers and/orone or more compressors to fluidly communication with one or moreadsorbent beds, and/or depressurizing equipment that may be utilized tofacilitate the startup mode cycle. In addition, other components andconfigurations may be utilized to provide the swing adsorption process,such as rapid cycle enabling hardware components (e.g., parallel channeladsorbent bed designs, rapid actuating valves, adsorbent bedconfigurations that integrate with other processes). Exemplary swingadsorption processes and configurations may also include U.S. PatentSer. Nos. 62/213,262; 62/213,267; 62/213,270; 62/213,273; 62/246,916;62/246,920; and 62/246,922, which are each incorporated by referenceherein.

Beneficially, the present techniques may be utilized to provide astartup process that does not involve an external drying process,involves minimal additional equipment for the startup process and may beoperated in a no-flare configurations.

In one or more embodiment, a startup mode process for a swing adsorptionprocess may include using a recycle startup mode or an external startupmode. For the external startup mode, the present techniques comprise aprocess for removing contaminants from a gaseous feed stream with aswing adsorption process, which may be utilized with one or moredownstream processes. The process comprising: a) performing aregeneration step (e.g., purge step), wherein the step comprises passingan external gas stream through an adsorbent bed unit to removecontaminants from an adsorbent bed within a housing of the adsorbent bedunit to form a purge product stream; b) performing one or moreadsorption steps, wherein each of the one or more adsorption stepscomprise passing a gaseous feed stream through an adsorbent bed unithaving an adsorbent bed to separate contaminants from the gaseous feedstream to form a product stream; c) determining whether the productstream is within a specification for at least one contaminant; d) if theproduct stream is within the specification (e.g., is below a certainthreshold), passing the product stream to a downstream process; and e)if the product stream is not within the specification (e.g., above acertain threshold), repeating the steps a) to d) for at least oneadditional cycle.

As another example for the external startup mode, a cyclical swingadsorption system may include a plurality of manifolds; a plurality ofadsorbent bed units coupled to the plurality of manifolds, and anexternal gas bypass valve in fluid communication with purge manifold andconfigured to provide a flow passage for an external gas stream from anexternal gas storage vessel to the purge manifold in a startup modeposition and configured to block the flow passage of the external gasstream from the external gas storage vessel to the purge manifold in anormal operation mode position. The plurality of manifolds comprise afeed manifold configured to pass a feed stream to the plurality ofadsorbent bed units during an adsorption step, a product manifoldconfigured to pass a product stream from the plurality of adsorbent bedunits during the adsorption step, a purge manifold configured to pass apurge stream to the plurality of adsorbent bed units during aregeneration step, a purge product manifold configured to pass a purgeproduct stream from the plurality of adsorbent bed units during theregeneration step. Each manifold of the plurality of manifolds isassociated with one swing adsorption process step of a plurality ofswing adsorption process steps. Each of the adsorbent bed unitscomprising a housing; an adsorbent material disposed within the housing;a plurality of valves, wherein at least one of the plurality of valvesis associated with one of the plurality of manifolds and is configuredto manage fluid flow along a flow path extending between the respectivemanifold and the adsorbent material.

In addition, the system or method may include certain features toenhance the operation of the system or method. For example, theplurality of valves may comprise one or more poppet valves; theplurality of manifolds and/or the plurality of adsorbent bed units maybe configured to operate at pressures between 0.1 bar absolute (bara)and 100 bara; the system may include a heating unit disposed upstream ofthe purge manifold and downstream of the external gas storage vessel,wherein the heating unit is configured to heat the external gas streamto a temperature in the range between a temperature in the range between450° F. and the gaseous feed stream temperature or between a temperaturein the range between 450° F. and greater than 100° F. of the gaseousfeed stream temperature; the system may include a conditioning unitdisposed downstream of the purge product manifold and upstream of theexternal gas storage vessel, wherein the conditioning unit is configuredto remove one or more contaminants from the purge product stream; theplurality of manifolds may further comprise a blowdown manifoldconfigured to pass a blowdown stream from the plurality of adsorbent bedunits during a blowdown step; and the system may include a liquefiednatural gas process unit in fluid communication with the adsorbent bedunit and configured to receive the product stream and separate theproduct stream into a final product stream and a flash fuel stream,wherein the flash fuel stream is passed to the purge manifold. Further,the external gas stream comprises a nitrogen stream comprisingpredominately nitrogen with less than 0.1 ppm of water, or may comprisea nitrogen stream comprising predominately nitrogen with less than 10ppm of water. The external gas stream may be a nitrogen containingstream having greater than one volume percent nitrogen based on thetotal volume of the feed stream.

For the external startup mode, the present techniques describe a processfor removing contaminants from a gaseous feed stream with a swingadsorption process. The process comprises passing a gaseous feed streamto a swing adsorption process that comprises a plurality of adsorbentbed units, each of the adsorbent bed units performs a swing adsorptioncycle that includes an adsorption step and a regeneration step; whereinthe swing adsorption cycle comprises: performing a first bed adsorptionstep for a first adsorbent bed unit of the plurality of adsorbent bedunits that comprises passing a gaseous feed stream through the firstadsorbent bed unit having a first adsorbent bed to separate one or morecontaminants from the gaseous feed stream to form a first productstream; and performing a second bed regeneration step for a secondadsorbent bed unit of the plurality of adsorbent bed units thatcomprises passing at least a portion of the first product stream throughthe second adsorbent bed unit having a second adsorbent bed to separateone or more contaminants from the second adsorbent bed to form a firstpurge product stream.

Further, in one or more embodiments, the present techniques describe aprocess for removing contaminants from a gaseous feed stream with aswing adsorption process. The process comprising: passing a gaseous feedstream to a swing adsorption process that comprises a plurality ofadsorbent bed units, each of the adsorbent bed units performs a swingadsorption cycle that includes an adsorption step and a regenerationstep; wherein the swing adsorption cycle comprises: performing aadsorption step for one of the plurality of adsorbent bed units thatcomprises passing a portion of the gaseous feed stream through the oneof the plurality of adsorbent bed units to remove one or morecontaminants from the gaseous feed stream and conduct away a productstream; and performing a regeneration step for the one of the pluralityof adsorbent bed units that comprises passing at least a portion of aproduct stream from another of the plurality of adsorbent bed unitsthrough the one of the plurality of adsorbent bed units to remove one ormore contaminants from the one of the plurality of adsorbent bed unitsand conduct away a purge product stream.

In yet another embodiment, a cyclical swing adsorption system isdescribed. The system includes: a plurality of manifolds, wherein theplurality of manifolds comprise a feed manifold configured to pass afeed stream to the plurality of adsorbent bed units during an adsorptionstep, a product manifold configured to pass a product stream from theplurality of adsorbent bed units during the adsorption step, a purgemanifold configured to pass a purge stream to the plurality of adsorbentbed units during a regeneration step, a purge product manifoldconfigured to pass a purge product stream from the plurality ofadsorbent bed units during the regeneration step, each manifold of theplurality of manifolds is associated with one swing adsorption processstep of a plurality of swing adsorption process steps; a plurality ofadsorbent bed units coupled to the plurality of manifolds, each of theadsorbent bed units comprising: a housing; an adsorbent materialdisposed within the housing; a plurality of valves, wherein at least oneof the plurality of valves is associated with one of the plurality ofmanifolds and is configured to manage fluid flow along a flow pathextending between the respective manifold and the adsorbent material; astartup mode bypass valve in fluid communication with purge manifold andthe product manifold and configured to provide a flow passage betweenthe product manifold and the purge manifold in a startup mode positionand configured to block the flow passage between the product manifoldand the purge manifold in a normal operation mode position.

In certain embodiments, the process and system may include someadditional variations. For example, the process may include: determiningwhether the first product stream is within a specification for acontaminant; if the first product stream is within the specification,passing at least a portion of the first product stream to a downstreamprocess; if the first product stream is not within the specification,performing a regeneration step for the first adsorbent bed unit thatcomprises passing a portion of a second product stream through the firstadsorbent bed unit to separate one or more contaminants from the firstadsorbent bed to form a second purge product stream, wherein the secondproduct stream is provided from another of the plurality of adsorbentbed units; and repeating the adsorbent step for the first adsorbent bedunit. As another example, the process may include mixing a slip stream(e.g., an overhead stream, such as overhead stream from NGL or fuel fromLNG) from the downstream process with the at least a portion of thefirst product stream prior to performing the second bed regenerationstep; and/or adjusting the amount of at least a portion of the firstproduct stream utilized in the second bed regeneration step based on theamount of slip stream (e.g., overhead stream) from the downstreamprocess. Also, the method may further comprise separating one or morecontaminants from the at least the portion of the first product streamprior to passing the at least the portion of the first product streamthrough the second adsorbent bed unit; and/or wherein the separatingfurther comprises reducing the pressure of the at least the portion ofthe first product stream by at least 10% relative to the pressure of thestream prior to the separating the one or more contaminants. By way ofexample, the feed stream may include CO₂ and water. The adsorbent bedunits may be configured to remove the water in a first group ofadsorbent beds and then pass the resulting product stream to remove CO₂in a second group of adsorbent beds. Alternatively, a portion of theproduct stream from one adsorbent bed may be conditioned to removecontaminants prior to passing the portion of the product stream to asecond adsorbent bed. The conditioning may include flash separation,pressure reduction, external contaminant removal process or similarremoval processes.

In other embodiments, the process and system may include additionalfeatures. For example, the plurality of valves comprise one or morepoppet valves; the plurality of manifolds and/or the plurality ofadsorbent bed units are configured to operate at pressures between 0.1bar absolute (bara) and 100 bara; and/or wherein the plurality ofmanifolds further comprise a blowdown manifold configured to pass ablowdown stream from the plurality of adsorbent bed units during ablowdown step. The cyclical swing adsorption system may furthercomprising a heating unit disposed upstream of the purge manifold anddownstream of the product manifold, wherein the heating unit isconfigured to heat the product stream to a temperature in the rangebetween 450° F. and greater than 100° F. of the gaseous feed streamtemperature or in the range between 450° F. and the gaseous feed streamtemperature; a separating unit disposed upstream of the purge manifoldand downstream of the heating unit, wherein the separating unit isconfigured to lessen the pressure of the product stream to a pressure inthe range between 0.1 bar absolute (bara) and 100 bara, which is lowerthan the pressure within the product stream or which may lower thepressure by at least 10%, by at least 20% or at least 30% relative tothe pressure of the product stream exiting the adsorbent bed (e.g.,lower the pressure of the product stream prior to the separating or atthe exit of the adsorbent bed); may further comprise a conditioning unitdisposed downstream of the purge product manifold and upstream of thefeed manifold, wherein the conditioning unit is configured to remove oneor more contaminants from the purge product stream; and/or may furthercomprise a liquefied natural gas process unit in fluid communicationwith the adsorbent bed unit and configured to receive the product streamand separate the product stream into a final product stream and a flashfuel stream, wherein the flash fuel stream is passed to the purgemanifold.

In other certain embodiments, the startup mode for the swing adsorptionprocess may be integrated with downstream equipment and processes. Thedownstream equipment and processes may include control freeze zone (CFZ)applications, niotrogen removal unit (NRU), cryogenic NGL recoveryapplications, LNG applications, and other such applications. Each ofthese different applications may include different specifications forthe feed stream in the respective process. For example, the startupprocess may involve dehydration upstream of a cryogenic NGL process oran LNG process and may be integrated with the respective downstreamequipment. As another example, the startup process may involve CO₂removal upstream of a cryogenic NGL process or the LNG process and maybe integrated with respective downstream equipment. Other embodimentsmay involve a combination of the two startup mode processes. The startupmethod may include using an external medium as part of the process,which may be a dry nitrogen stream. Also, the startup method may involveprogressively dehydrating and/or cleaning the adsorbent beds by passingthe product stream through one or more adsorbent beds. Further, thestartup mode may be integrated with downstream processes, such ascryogenic NGL processes and/or LNG processes. In addition, the startupmode process may involve performing the startup mode cycle with minimalflaring or no flaring.

In certain embodiments, the system utilizes a combined swing adsorptionprocess, which combines TSA and PSA, for treating of pipeline qualitynatural gas to remove contaminants for the stream to satisfy LNGspecifications. The swing adsorption process, which may be a rapid cycleprocess, is used to treat natural gas that is at pipeline specifications(e.g., a feed stream of predominately hydrocarbons along with less thanor equal to about 2% volume CO₂ and/or less than or equal to 4 ppm H₂S)to form a stream satisfying the LNG specifications (e.g., less than 50ppm CO₂ and less than about 4 ppm H₂S). The product stream, which may bethe LNG feed stream, may have greater than 98 volume percenthydrocarbons based on the total volume of the product stream, while theCO₂ and water content are below certain thresholds. The LNGspecifications and cryogenic NGL specifications may involve the CO₂content to be less than or equal to 50 ppm, while the water content ofthe stream may be less than 0.1 ppm.

Further, the gaseous feed stream may include various components. Forexample, the gaseous feed stream may be a hydrocarbon containing streamhaving greater than one volume percent hydrocarbons based on the totalvolume of the feed stream. In addition, the gaseous feed stream maycomprise hydrocarbons and CO₂, wherein the CO₂ content is in the rangeof two hundred parts per million volume and less than or equal to about2% volume of the gaseous feed stream. Further, the swing adsorptionprocess may be configured to lower the carbon dioxide (CO₂) level toless than 50 parts per million. As another example, the gaseous feedstream may include hydrocarbons and H₂O. For example, the gaseous feedstream may be that the H₂O is in the range of 0.2 parts per millionvolume to saturation levels in the gaseous feed stream or the H₂O is inthe range of 100 parts per million volume to 1500 parts per millionvolume.

In certain aspects, as described further below, the present techniquesmay involve using a high temperature stream that is provided to theadsorbent beds as part of the purge step to heat the adsorbent bed. Thestream, which may be referred to as the purge stream (e.g., the externalstream or a portion of the product stream), may be heated to temperaturemay be less than 550° F., may be less than 500° F., less than 450° F. ormay be less than 350° F., and may be the gaseous feed streamtemperature, greater than 50° F. of the gaseous feed stream temperature,greater than 100° F. of the gaseous feed stream temperature or greaterthan 250° F. of the gaseous feed stream temperature. For example, thestream used during the purge step of the startup mode cycle may be atemperature in the range between 500° F. and greater than 50° F. of thegaseous feed stream temperature, in the range between 450° F. and thegaseous feed stream temperature, in the range between 450° F. andgreater than 100° F. of the gaseous feed stream temperature or 400° F.and greater than 200° F. of the gaseous feed stream temperature. Thestream (purge stream or external stream) pressure may be in the rangebetween 0.01 bara and 100 bara, between 1 bara and 80 bara, or between 2bara and 50 bara.

Further, the present techniques may not remove all of the contaminant(e.g., H₂O and CO₂) adsorbed in the bed during the purge step of thestartup mode process, but remove a portion of the contaminants such thatthe product end of the adsorbent bed has a contaminant loadingsufficiently low to provide a product stream with less thanspecifications. Accordingly, the product end of the adsorbent bed may bemaintained nearly free of contaminants (e.g., the CO₂ loading for theregion near the product end is less than 1 millimole per gram (mmol/g),less than 0.5 mmol/g or less than 0.1 mmol/g). The loading level ofcontaminant may be lower on the feed side of the adsorbent bed duringthe purge step, but the length of adsorbent bed that containscontaminants is reduced during the purge step. For example, a feedregion may be a specific portion of the adsorbent bed from the feed endof the adsorbent bed to 10% of the bed length, from the feed end of theadsorbent bed to 25% of the bed length or from the feed end of theadsorbent bed to 40% of the bed length. The product region may be aspecific portion of the adsorbent bed from the product end of theadsorbent bed to 10% of the bed length, from the product end of theadsorbent bed to 25% of the bed length or from the product end of theadsorbent bed to 40% of the bed length. The movement of the contaminantsfront back during purge step and forward during the adsorption step isthe basis of the swing capacity of the process. In part, this isachieved by using a limited, cost effective quantity of purge gas in thepurge steam along with the heating of the adsorbent bed in this processand configuration.

The present techniques may involve using two or more adsorbent beds,which are operated on similar cycle that are performing different stepsof the cycles (e.g., not synchronized with each other) to maintain asteady flow of fluids for the various streams (e.g., feed stream,product stream, heating stream, and purge stream).

Further, in other embodiments, the pressure of the different streams maybe varied. For example, the feed stream may involve a feed pressure thatis within the in the range between 0.01 bara and 100 bara, between 1bara and 80 bara, or between 2 bara and 50 bara, but is not necessarilylimited to this range. The feed temperature may be in the range between0° F. and 200° F., in the range between 20° F. and 175° F. or in therange between 40° F. and 150° F. The blowdown pressure, heatingpressure, and purge pressure may be adjusted depending on the cycle, maydepend upon the adsorbent material being utilized and/or may range fromvacuum to feed pressure. For example, if the adsorbent material iszeolite 4A, the blowdown pressure range may be between 0.01 bara to 50bara, or more preferably in a range between 1 bara and 15 bara. Thisexample may depend on the feed concentration of CO₂. Also, in otherembodiments, the depressurization steps may be adjusted such that thepressure swing is achieved in stages to vary the amount of methanedesorbing during each step, if any. Additionally, a heating loop may beintroduced and the heating pressure in the heating loop may be operatedat a pressure different from the purge pressure or blowdown pressure inthe respective steps. Also, certain embodiments may include no pressureswing, but may rely upon temperature swing for the regeneration step.Similarly, in the other embodiments, no temperature swing may beperformed and the regeneration step may be performed by pressure swing.

Furthermore, the above process may be used for startup mode processesthat separate two or more contaminants from the feed stream (e.g., twoswing adsorption processes operated in series with each other). Forexample, the feed stream may subjected to a dehydration swing adsorptionprocess, then a CO₂ removal swing adsorption process, and the resultingproduct may be subjected to a downstream process, such as cryogenic NGLor LNG recovery. The startup mode for the dehydration and the CO₂removal processes may involve the recycle startup process and/or theexternal startup process. As one example, the dehydration process mayinvolve the external startup process. Then, once the product streamsatisfies the desired specification for water removal, the productstream may be used by the CO₂ removal as part of the external startupstream. Alternatively, the dehydration process may involve the externalstartup process and the CO₂ removal process may perform the recycleprocess and may mix the purge stream with the feed stream to thedehydration process.

In certain configurations, an integrated rapid cycle adsorption systemmay be utilized to remove multiple contaminants (e.g., water and CO₂).Suitable adsorbent material or adsorbent layers may be utilized toprovide the dehydration, which may be the same or different from theadsorbent material used to in the removal of other contaminants, such asCO₂.

Moreover, the present techniques may include a specific process flowduring normal operation mode to remove contaminants, such as CO₂ and/orwater. For example, the process may include an adsorbent step and aregeneration step, which form the cycle. The adsorbent step may includepassing a gaseous feed stream at a feed pressure and feed temperaturethrough an adsorbent bed unit to separate one or more contaminants fromthe gaseous feed stream to form a product stream. The feed stream may bepassed through the adsorbent bed in a forward direction (e.g., from thefeed end of the adsorbent bed to the product end of the adsorbent bed).Then, the flow of the gaseous feed stream may be interrupted for aregeneration step. The regeneration step may include one or moredepressurization steps, one or more heating steps, and/or one or morepurge steps. The depressurization steps, which may be or include ablowdown step, may include reducing the pressure of the adsorbent bedunit by a predetermined amount for each successive depressurizationstep, which may be a single step and/or multiple steps. Thedepressurization step may be provided in a forward direction or maypreferably be provided in a countercurrent direction (e.g., from theproduct end of the adsorbent bed to the feed end of the adsorbent bed).The heating step may include passing a heating stream into the adsorbentbed unit, which may be a recycled stream through the heating loop and isused to heat the adsorbent material. The purge step may include passinga purge stream into the adsorbent bed unit, which may be a once throughpurge step and the purge stream may be provided in countercurrent flowrelative to the feed stream. The purge stream may be provided at a purgetemperature and purge pressure, which may include the purge temperatureand purge pressure being similar to the heating temperature and heatingpressure used in the heating step. Then, the cycle may be repeated foradditional streams. Additionally, the process may include one or morere-pressurization steps after the purge step and prior to the adsorptionstep. The one or more re-pressurization steps may be performed, whereinthe pressure within the adsorbent bed unit is increased with eachre-pressurization step by a predetermined amount with each successivere-pressurization step. The cycle duration for normal operation mode maybe for a period greater than 1 second and less than 600 seconds, for aperiod greater than 2 second and less than 300 seconds, for a periodgreater than 2 second and less than 180 seconds, for a period greaterthan 5 second and less than 150 seconds or for a period greater than 5second and less than 90 seconds.

In other configurations, the startup mode may involve lower flow ratesand longer cycles. For example, the initial flow rate may be 25% of thenormal flow rate utilized during normal operation mode, which may have astartup mode cycle time of four times the normal operation model cycletime. This initial flow rate may be increased in a steady manner or invarious increments until the normal operation mode is reached. By way ofexample, the startup mode cycle duration may be for a period greaterthan 1 second and less than 2400 seconds, for a period greater than 1second and less than 1500 seconds, for a period greater than 1 secondand less than 1000 seconds, for a period greater than 1 second and lessthan 600 seconds, for a period greater than 2 second and less than 800seconds, for a period greater than 2 second and less than 400 seconds,for a period greater than 5 second and less than 150 seconds or for aperiod greater than 5 second and less than 90 seconds.

In yet other configurations, the startup mode may involve installationof adsorbent beds that are partially or completely devoid of thecontaminant being removed. By way of example, if the swing adsorptionprocess is primarily configured to remove water, then a partially ortotally dehydrated adsorbent bed may be installed in the system. Duringthe start mode, a feed stream is passed to the adsorbent bed, which maybe as a wet gas, and a product stream, which may be a dry stream, isconducted away and may be used as a purge stream to a differentadsorbent bed. Alternatively, another method may involve installation ofan adsorbent bed in the swing adsorption process that is treated orconditioned such that the contaminant replaces a different molecule thatis already adsorbed on the adsorbent bed. By way of example, if theswing adsorption process is primarily configured to remove CO₂, then theadsorbent bed may include adsorbed particles, such as water, which maybe installed in the system. During the start mode, a feed stream ispassed to the adsorbent bed, which may include the CO₂ contaminants, anda product stream may be conducted away and may be used as a purge streamto a different adsorbent bed.

In one or more embodiments, the present techniques can be used for anytype of swing adsorption process. Non-limiting swing adsorptionprocesses for which the present techniques may be used include pressureswing adsorption (PSA), vacuum pressure swing adsorption (VPSA),temperature swing adsorption (TSA), partial pressure swing adsorption(PPSA), rapid cycle pressure swing adsorption (RCPSA), rapid cyclethermal swing adsorption (RCTSA), rapid cycle partial pressure swingadsorption (RCPPSA), as well as combinations of these processes. Forexample, the preferred swing adsorption process may include a combinedpressure swing adsorption and temperature swing adsorption, which may beperformed as a rapid cycle process. Exemplary swing adsorption processesare further described in U.S. Patent Ser. Nos. 62/213,262; 62/213,267;62/213,270; 62/213,273; 62/246,916; 62/246,920; and 62/246,922 and U.S.Patent Application Publication Nos. 2008/0282892, 2008/0282887,2008/0282886, 2008/0282885, 2008/0282884 and 20140013955, which are eachherein incorporated by reference in their entirety.

In other configurations, the present techniques may involve variousvariations. The method may include mixing a slip stream from thedownstream process with the at least a portion of the first productstream prior to performing the second bed regeneration step; heating theat least a portion of the first product stream prior to passing the atleast the portion of the first product stream through the secondadsorbent bed unit, wherein the at least a portion of the first productstream is heated to a temperature in the range between a temperature inthe range between 450° F. and the gaseous feed stream temperature;heating the purge product stream, wherein the purge product stream isheated to a temperature 10° F. greater than the dew point of the purgeproduct stream; separating one or more contaminants from the purgeproduct stream to form conditioned purge product stream and mixing theconditioned purge product stream with the gaseous feed stream upstreamof the swing adsorption process; wherein the downstream process is aliquefied natural gas (LNG) process that comprises an LNG process unitand separating a flash fuel stream from the LNG process unit to mixedwith the at least a portion of the first product stream prior to thesecond adsorbent bed unit; wherein the downstream process is a cryogenicnatural gas liquid recovery (NGL) process having a NGL process unit; andfurther comprising separating an overhead stream from the NGL processunit to be utilized as at least a portion of the purge stream; providingan external gas stream and mixing the external gas stream with theportion of the first product stream, wherein the external gas stream isa nitrogen containing stream having greater than one volume percentnitrogen based on the total volume of the external stream; and/or aseparating unit disposed upstream of the purge manifold and downstreamof the heating unit, wherein the separating unit is configured to lessenthe pressure of the product stream by at least 10% as compared to thepressure of the product stream upstream of the separating unit.

Further still, in one or more embodiments, a variety of adsorbentmaterials may be used to provide the mechanism for the separations.Examples include zeolite 3A, 4A, 5A, ZK4 and MOF-74. However, theprocess is not limited to these adsorbent materials, and others may beused as well. The present techniques may be further understood withreference to the FIGS. 1 to 12 below.

FIG. 1 is a three-dimensional diagram of the swing adsorption system 100having six adsorbent bed units and interconnecting piping. While thisconfiguration is a specific example, the present techniques broadlyrelate to adsorbent bed units that can be deployed in a symmetricalorientation, or non-symmetrical orientation and/or combination of aplurality of hardware skids. Further, this specific configuration is forexemplary purposes as other configurations may include different numbersof adsorbent bed units.

In this system, the adsorbent bed units, such as adsorbent bed unit 102,may be configured for a cyclical swing adsorption process for removingcontaminants from feed streams (e.g., fluids, gaseous or liquids). Forexample, the adsorbent bed unit 102 may include various conduits (e.g.,conduit 104) for managing the flow of fluids through, to or from theadsorbent bed within the adsorbent bed unit 102. These conduits from theadsorbent bed units 102 may be coupled to a manifold (e.g., manifold106) to distribute the flow to, from or between components. Theadsorbent bed within an adsorbent bed unit may separate one or morecontaminants from the feed stream to form a product stream. As may beappreciated, the adsorbent bed units may include other conduits tocontrol other fluid steams as part of the process, such as purgestreams, depressurizations streams, and the like. In particular, theadsorbent bed units may include startup mode equipment, such as one ormore heating units (not shown), one or more external gas sourcemanifolds, which may be one of the manifolds 106) and one or moreexpanders, as noted further below, which is used as part of the startupmode for the adsorbent beds. Further, the adsorbent bed unit may alsoinclude one or more equalization vessels, such as equalization vessel108, which are dedicated to the adsorbent bed unit and may be dedicatedto one or more step in the swing adsorption process. The equalizationvessel 108 may be used to store the external stream, such as nitrogenfor use in the startup mode cycle.

As an example, which is discussed further below in FIG. 2, the adsorbentbed unit 102 may include a housing, which may include a head portion andother body portions, that forms a substantially gas impermeablepartition, an adsorbent bed disposed within the housing and a pluralityof valves (e.g., poppet valves) providing fluid flow passages throughopenings in the housing between the interior region of the housing andlocations external to the interior region of the housing. Each of thepoppet valves may include a disk element that is seatable within thehead or a disk element that is seatable within a separate valve seatinserted within the head (not shown). The configuration of the poppetvalves may be any variety of valve patterns or configuration of types ofpoppet valves. As an example, the adsorbent bed unit may include one ormore poppet valves, each in flow communication with a different conduitassociated with different streams. The poppet valves may provide fluidcommunication between the adsorbent bed and one of the respectiveconduits, manifolds or headers. The term “in direct flow communication”or “in direct fluid communication” means in direct flow communicationwithout intervening valves or other closure means for obstructing flow.As may be appreciated, other variations may also be envisioned withinthe scope of the present techniques.

The adsorbent bed comprises a solid adsorbent material capable ofadsorbing one or more components from the feed stream. Such solidadsorbent materials are selected to be durable against the physical andchemical conditions within the adsorbent bed unit 102 and can includemetallic, ceramic, or other materials, depending on the adsorptionprocess. Further examples of adsorbent materials are noted furtherbelow.

FIG. 2 is a diagram of a portion of an adsorbent bed unit 200 havingvalve assemblies and manifolds in accordance with an embodiment of thepresent techniques. The portion of the adsorbent bed unit 200, which maybe a portion of the adsorbent bed unit 102 of FIG. 1, includes a housingor body, which may include a cylindrical wall 214 and cylindricalinsulation layer 216 along with an upper head 218 and a lower head 220.An adsorbent bed 210 is disposed between an upper head 218 and a lowerhead 220 and the insulation layer 216, resulting in an upper open zone,and lower open zone, which open zones are comprised substantially ofopen flow path volume. Such open flow path volume in adsorbent bed unitcontains gas that has to be managed for the various steps. The housingmay be configured to maintain a pressure from 0 bara (bar absolute) to150 bara within the interior region.

The upper head 218 and lower head 220 contain openings in which valvestructures can be inserted, such as valve assemblies 222 to 240,respectively (e.g., poppet valves). The upper or lower open flow pathvolume between the respective head 218 or 220 and adsorbent bed 210 canalso contain distribution lines (not shown) which directly introducefluids into the adsorbent bed 210. The upper head 218 contains variousopenings (not show) to provide flow passages through the inlet manifolds242 and 244 and the outlet manifolds 248, 250 and 252, while the lowerhead 220 contains various openings (not shown) to provide flow passagesthrough the inlet manifold 254 and the outlet manifolds 256, 258 and260. Disposed in fluid communication with the respective manifolds 242to 260 are the valve assemblies 222 to 240. If the valve assemblies 222to 240 are poppet valves, each may include a disk element connected to astem element which can be positioned within a bushing or valve guide.The stem element may be connected to an actuating means, such asactuating means (not shown), which is configured to have the respectivevalve impart linear motion to the respective stem. As may beappreciated, the actuating means may be operated independently fordifferent steps in the process to activate a single valve or a singleactuating means may be utilized to control two or more valves. Further,while the openings may be substantially similar in size, the openingsand inlet valves for inlet manifolds may have a smaller diameter thanthose for outlet manifolds, given that the gas volumes passing throughthe inlets may tend to be lower than product volumes passing through theoutlets.

In swing adsorption processes, the cycle involves two or more steps thateach has a certain time interval, which are summed together to be thecycle time or cycle duration. These steps include regeneration of theadsorbent bed following the adsorption step using a variety of methodsincluding pressure swing, vacuum swing, temperature swing, purging (viaany suitable type of purge fluid for the process), and combinationsthereof. As an example, a PSA cycle may include the steps of adsorption,depressurization, purging, and re-pressurization. When performing theseparation at high pressure, depressurization and re-pressurization(which may be referred to as equalization) may be performed in multiplesteps to reduce the pressure change for each step and enhanceefficiency. In some swing adsorption processes, such as rapid cycleswing adsorption processes, a substantial portion of the total cycletime is involved in the regeneration of the adsorbent bed. Accordingly,any reductions in the amount of time for regeneration results in areduction of the total cycle time. This reduction may also reduce theoverall size of the swing adsorption system.

Further, in startup mode for the swing adsorption process, one or moreof the manifolds and associated valves may be utilized as a dedicatedflow path for one or more startup streams. For example, during theadsorption or feed step, the manifold 242 and valve assembly 222 may beutilized to pass the feed gas stream to the adsorbent bed 210, while thevalve assembly 236 and manifold 256 may be used to conduct away theproduct stream from the adsorbent bed 210. During the regeneration orpurge step, the manifold 244 and valve assembly 224 may be utilized topass the external gas stream or recycle stream to the adsorbent bed 210,while the valve assembly 236 and manifold 256 may be used to conductaway the purge product stream from the adsorbent bed 210. Accordingly,the manifold 244 and valve assembly 224 may be utilized for startup modeprocesses, but remain inactive during normal operation mode. As may beappreciated, the purge stream may be configured to flow counter currentto the feed stream in other embodiments.

Alternatively, the startup mode for the swing adsorption process mayinvolve sharing one or more of the manifolds and associated valvesduring the normal operation mode and during startup mode. For example,the manifold 242 and valve assembly 222 may be utilized to feed thegaseous feed stream to the adsorbent bed 210 during startup mode andduring normal operations, while the valve assembly 236 and manifold 256may be used to conduct away the product stream from the adsorbent bed210 may be used to conduct away the product stream during startup modeand during normal operation mode. During the regeneration or purge step,the manifold 254 and valve assembly 232 may be utilized to pass theexternal gas stream or recycle stream to the adsorbent bed 210 forstartup mode and to pass the purge stream to the adsorbent bed 210 fornormal operation mode, while the valve assembly 226 and manifold 248 maybe used to conduct away the purge product stream from the adsorbent bed210 during startup mode and normal operation mode. Beneficially, thisconfiguration may be utilized to lessen any additional valves orconnections for startup mode for adsorbent bed unit configurations thatare subject to space limitations on the respective heads.

During normal operation mode, a gaseous feed stream may be subject tovarious processes to form a NGL stream or a LNG stream. For example, theprocess may include a mercury removal unit to remove mercury from aninput stream; a filter to remove both particular and liquid droplets; aswing adsorption unit to remove one or more contaminants, such as H₂O,CO₂ and sulfur containing species; a LNG process unit or NGL processunit to process the resulting stream into a final product that may beused for sales, shipment or storage. In addition, the configuration mayinclude one or more of a heating loop, a compressor, a heating unitand/or a storage vessel.

As noted above, the present techniques include various procedures thatmay be utilized for the startup mode of the swing adsorption process.The startup mode may include an external startup mode. The externalstartup mode may include performing an adsorption step and then aregeneration step for each of the adsorbent beds. The adsorption stepmay include passing a gaseous feed stream through the adsorbent bed toadsorb one or more contaminants from the gaseous feed stream andconducting away the resulting product stream from the adsorbent bedunit. The resulting product stream may be passed to downstreamprocessing equipment and/or may be recycled to the adsorbent bed oranother adsorbent bed unit as the gaseous feed stream. The regenerationstep may include passing an external stream through the adsorbent bed toremove one or more contaminants from the adsorbent bed unit (e.g., aportion of the contaminants within the adsorbent bed unit or within thevoids of the adsorbent bed) and conduct away the purge product streamfrom the adsorbent bed unit. The purge product stream may be set toflare or may be combined with fuel gas.

As an example, FIG. 3 is an exemplary flow chart for performing anexternal startup mode of a swing adsorption process in accordance withan embodiment of the present techniques. In this flow chart 300, thestartup mode process may involve the use of an external gas stream toremove one or more contaminants from the adsorbent beds as part of thestartup mode cycle. Further, the startup mode process may includeoperating two or more adsorbent bed units, which may each be performingdifferent steps in the startup mode cycle. For each of the adsorbent bedunits, the swing adsorption process involves a startup mode processusing an external stream, as shown in blocks 302 to 308, which isdescribed as being performed for a single adsorbent bed unit forsimplicity. Then, the adsorbent bed units may be used with thedownstream equipment, as shown in blocks 310 to 316, and normaloperations mode are begun, as shown in block 318. The external gasstream may include nitrogen and/or methane, as noted above. The externalstream may comprise predominately nitrogen and/or methane with less than0.1 ppm of water, or less than 10 ppm of water. The external gas streammay be a nitrogen containing stream having greater than one volumepercent nitrogen based on the total volume of the feed stream.

The process begins by performing the startup mode process for theadsorbent bed units of the swing adsorption process, as shown in blocks302 to 308. At block 302, a regeneration step is performed for theadsorbent bed with an external stream. The external stream may includenitrogen or methane and may be a dry stream (e.g., less than 10 ppm ofwater, less than 1 ppm of water, or less than 0.1 ppm of water). Theregeneration step, which may be one or more purge steps may includepassing the external stream through the adsorbent bed to create a purgeproduct stream that is conducted away from the adsorbent bed unit. Theproduct purge stream may include the external stream and a portion ofthe contaminants within the adsorbent bed. This product purge stream maybe intermingled with a fuel gas stream or may be flared. Further, theexternal stream may be subjected to a heating step prior to being passedto the adsorbent bed. The heating step may heat the external stream to atemperature less than 550° F., less than 500° F., less than 450° F. orless than 350° F., and may be the gaseous feed stream temperature,greater than 50° F. of the gaseous feed stream temperature, greater than100° F. of the gaseous feed stream temperature or greater than 250° F.of the gaseous feed stream temperature. For example, the external streamused during the purge step may be a temperature in the range between500° F. and greater than 50° F. of the gaseous feed stream temperature,in the range between 450° F. and the gaseous feed stream temperature, inthe range between 450° F. and greater than 100° F. of the gaseous feedstream temperature or 400° F. and greater than 200° F. of the gaseousfeed stream temperature. The heating of the external stream may includepassing the stream through a heat exchanger or similar heating unit toincrease the temperature of the external stream. At block 304, anadsorption step is performed for the adsorbent bed. The adsorption stepmay include passing a gaseous feed stream through the adsorbent bed toremove one or more contaminants from the gaseous feed stream and tocreate a product stream that is conducted away from the adsorbent bedunit. At block 306, the product stream may be measured. The productstream may be measured by taking samples, using a moisture analyzer,using a gas chromatograph or using another gas component analysisequipment. Then, at block 308, a determination may be made whether theproduct stream is within specification. This determination may includeanalyzing the product stream to determine the level of one or more ofthe contaminants within the product stream. If the product stream iswithin specification (e.g., contaminants are at or below a specificthreshold), the product stream may be passed to downstream processes.However, if the product stream is not within specifications (e.g.,contaminants are above a specific threshold), the product stream may berecycled to be intermingled with the gaseous feed stream and utilized aspart of the adsorption step, as shown in block 304.

Once the adsorbent bed units are passing the product stream to thedownstream process, the product stream may be used with the downstreamequipment, as shown in blocks 310 to 316. At block 310, the startup modefor the downstream equipment may begin. The startup mode for thedownstream equipment may involve various steps prior to the passing ofproduct stream to the downstream equipment or may begin once the productstream is passed to the downstream equipment. The downstream processesmay include a CFZ process, a cryogenic NGL recovery process, or an LNGprocess, with the associated equipment for each. Further, during thedownstream startup mode sequence, the adsorbent bed units may continueto utilize the external stream for the purge step. At block 312, a purgestream may be passed to the adsorbent bed units from the downstreamprocess. The purge stream may include an overhead stream or a slipstream from the downstream process. By way of example, the purge streamfrom an NGL facility may be the demethanizer overhead, or the purgestream may be a fuel gas stream for an LNG facility. Then, at block 314,the amount of external stream utilized in the purge step may beadjusted. The adjustment may be based on the amount of the purge streambeing provided to the adsorbent bed units. For example, the flow rate ofthe external stream may be lowered by 10%, 50%, or 90% based on theamount of purge stream from the downstream processes and the desiredflow rate. At block 316, the flow of the external stream may beinterrupted. The flow of the external stream may be interrupted once thedownstream process is producing a sufficient amount of purge stream atconditions close to steady operating conditions.

Once the startup mode process is complete, the normal operation mode maybegin, as shown in block 318. At block 318, normal operation mode isbegun. The normal operation mode may include passing the gaseous feedstream is passed to the adsorbent bed units for the swing adsorptionprocess to remove contaminants and pass the product stream to thedownstream process. Then, the downstream process may pass the productstream through the various downstream equipment to produce a finalproduct stream. The downstream process may also pass a purge stream tothe swing adsorption process, which may be utilized during theregeneration step to remove contaminants from the adsorbent beds withinthe adsorbent bed units.

As a specific example, the feed stream may be a natural gas stream thatpredominately contains hydrocarbons, the external stream may be anitrogen stream and the contaminants within the adsorbent bed may bewater. During the purge step for the respective adsorbent bed, thenitrogen stream is passed through the adsorbent bed and water interactswith the nitrogen stream to form the purge product stream, whichincludes the nitrogen and the portion of the water removed from theadsorbent bed.

In addition, the product stream from the adsorbent bed units may beutilized in the startup mode process for one or more downstream units,such as a demethanizer or a liquefaction train. As the downstreamprocesses and units are being started, the spent adsorbent beds may beregenerated using the dry nitrogen stream as the purge stream. The drynitrogen stream may be heated. Alternatively, a heated slip stream fromthe product side may also be used to regenerate the adsorbent bedsduring the purge step. Once the downstream processes begin normaloperation mode, the purge stream may be adjusted to be provided from aresidue gas stream, a fuel gas stream or other suitable stream from oneof the downstream processes.

In certain embodiments, the purge product stream may be subjected toprocesses to remove the contaminants from the external stream, such thatthe cleaned purge product stream may be recycled to the adsorbent bedunits as the external stream or intermingled with the external stream.For example, if the external stream is a nitrogen stream and thecontaminant is water, the purge product stream may be heated and thenmay be subjected to a pressure drop to separate the water from thenitrogen in the purge product stream. In this manner, the nitrogen maybe regenerated and recycled to the adsorbent beds to remove additionalwater from the adsorbent beds during a subsequent purge step.

As further enhancements, the operating conditions may be adjusted duringthe external startup mode to manage the removal of contaminants from theadsorbent beds. By way of example, flow rate may be in a range between25 and 1000 million standard cubic feet per day (MSCFD) during normaloperation mode, while the flow rate may be in the range between 6.25 and500 MSCFD for startup mode. The flow rate may be increased duringsubsequent purge steps until normal operation mode flow rates arereached. Also, the pressure range of the external stream may be in apressure range between atmospheric pressure and fifty psi aboveatmospheric pressure. In addition, the temperature of the externalstream may be within a temperature range between 20° Celsius (C) aboveatmospheric temperature and 150° C. above atmospheric temperature.Further, the temperature of the external stream may be less than 550°F., less than 500° F., less than 450° F. or less than 350° F., and maybe the gaseous feed stream temperature, greater than 50° F. of thegaseous feed stream temperature, greater than 100° F. of the gaseousfeed stream temperature or greater than 250° F. of the gaseous feedstream temperature. For example, the external stream used during thepurge step may be a temperature in the range between 500° F. and greaterthan 50° F. of the gaseous feed stream temperature, in the range between450° F. and the gaseous feed stream temperature, in the range between450° F. and greater than 100° F. of the gaseous feed stream temperatureor 400° F. and greater than 200° F. of the gaseous feed streamtemperature.

To support the external startup mode process, a configuration of theswing adsorption process may include additional bypass conduits andmanifold to pass the external stream to the adsorbent bed units duringthe purge step. The external stream may be provided from an externalsource vessel through an external source conduit that is in fluidcommunication with purge manifold. In addition, the configuration mayinclude one or more heating units that are upstream of the purgemanifold and configured to heat the external stream prior to passingthrough the adsorbent bed units and/or that are downstream of the purgeproduct manifold and configured to heat the purge product stream. Theheating unit may include a heat exchanger, a furnace, or the like. Theconfiguration may also include one or more separation units configuredto separate one or more contaminants from the purge product stream. Theseparation units may be a flash separation vessel that is configured tolower the pressure of the stream to separate the contaminants from theremaining portion of the purge product stream or may be an adsorptionunit that interacts with the contaminants to separates the contaminantsfrom the remaining portion of the purge product stream. The contaminantsmay be conducted away from the process, while the remaining portion ofthe purge product stream may be passed to one or more regenerationunits. The regeneration units may be utilized to further purify theremaining portion of the purge product stream and/or compress theremaining portion of the purge product stream to form the externalstream that is passed to the adsorbent beds.

As an alternative method, the startup mode may include a recycle startupmode. The recycle startup mode may include performing an adsorption stepand then a regeneration step for each of the adsorbent beds, whichinvolves passing the product stream between adsorbent beds. Theadsorption step may include passing a gaseous feed stream through theadsorbent bed to adsorb one or more contaminants from the gaseous feedstream and conducting away the resulting product stream from theadsorbent bed unit. The resulting product stream may be passed anotheror second adsorbent bed that is performing the regeneration step. Theproduct stream, which is utilized as the purge stream, may pass throughthe adsorbent bed to remove one or more contaminants from the adsorbentbed unit (e.g., a portion of the contaminants within the adsorbent bedunit or within the voids of the adsorbent bed) and conduct away thepurge product stream from the adsorbent bed unit. The purge productstream may be set to flare or may be combined with a fuel gas stream.

As may be appreciated, multiple adsorbent bed units may be utilized inthe process. Each of these adsorbent bed units may be performing thestartup mode sequence, but be performing different steps. For example,some of the adsorbent bed units may be performing the adsorption stepand others are performing the purge step at any instance.

As an example, FIG. 4 is an exemplary flow chart for performing arecycle startup mode of a swing adsorption process in accordance with anembodiment of the present techniques. In this flow chart 400, thestartup mode process involves the use of the product stream from oneadsorbent bed unit as the purge stream for another adsorbent bed unitperforming a regeneration step. In this process, two or more adsorbentbed units are each performing different steps in the startup mode cycle.For each of the adsorbent bed units, the swing adsorption processinvolves a startup mode process using the product stream as the purgestream, as shown in blocks 402 to 410, which is described as beingperformed for two adsorbent bed units for simplicity. Then, theadsorbent bed units may be used with the downstream equipment, as shownin blocks 412 to 418, and normal operations mode are begun, as shown inblock 420.

The process begins by performing the startup mode process for theadsorbent bed units of the swing adsorption process, as shown in blocks402 to 408. At block 402, an adsorption step is performed for a firstadsorbent bed unit. The adsorption step may include passing a gaseousfeed stream through the adsorbent bed to remove one or more contaminantsfrom the gaseous feed stream and to create a product stream that isconducted away from the adsorbent bed unit. At block 404, the productstream may be measured. The product stream may be measured by takingsamples, using a moisture analyzer, using a gas chromatograph or usinganother gas component analysis equipment. Then, at block 406, adetermination may be made whether the product stream is withinspecification. This determination may include analyzing the productstream to determine the level of one or more of the contaminants withinthe product stream. If the product stream is within specification (e.g.,contaminants are at or below a specific threshold), the product streammay be passed to downstream processes. However, if the product stream isnot within specifications (e.g., contaminants are above a specificthreshold), a portion of the product stream is passed to a secondadsorbent bed unit performing its regeneration step, as shown in block408. The least a portion of the product stream may be greater than 5% ofthe product stream, greater than 50% of the product stream or greaterthan 75% of the product stream. The purge product stream from the secondadsorbent bed unit may be flared or may be mixed with a fuel gas stream.At block 410, a regeneration step for the first adsorbent bed unit usingthe product stream from another adsorbent bed unit is performed. Theproduct stream from another adsorbent bed unit may be from the secondadsorbent bed unit or one of the other adsorbent bed units in the swingadsorption process configuration that is performing its adsorption step.The product stream from another adsorbent bed unit may include passingthe product stream as the purge stream through the first adsorbent bedunit to create a purge product stream that is conducted away from thefirst adsorbent bed unit. The product purge stream may include theproduct stream and a portion of the contaminants within the firstadsorbent bed unit. This product purge stream may be intermingled with afuel gas stream or may be flared.

Once the product stream is within specification, the product stream maybe used with the downstream equipment, as shown in blocks 412 to 418. Atblock 412, the startup mode for the downstream equipment may begin. Thestartup mode for the downstream equipment may involve various stepsprior to the passing of product stream to the downstream equipment ormay begin once the product stream is passed to the downstream equipment.The downstream processes may include a CFZ process, a cryogenic NGLrecovery process, or an LNG process, with the associated equipment foreach. While the downstream process is beginning startup mode, theadsorbent bed units may use a portion of the product stream as the purgesteam for the regeneration steps of the adsorbent bed units. At block414, a purge stream may be passed to the adsorbent bed units from thedownstream process. The purge stream may include an overhead stream or aslip stream from the downstream process. By way of example, the purgestream from an NGL facility may be the demethanizer overhead, or thepurge stream may be a fuel gas stream for an LNG facility. Then, atblock 416, the amount of product stream utilized in the regenerationstep may be adjusted. The adjustment may be based on the amount of thepurge stream being provided to the adsorbent bed units. At block 418,the diversion of flow of the product stream may be interrupted. The flowof the product stream may be lessened and interrupted once thedownstream process is producing a sufficient amount of purge stream.

Once the startup mode process is complete, the normal operation mode maybegin, as shown in block 420. At block 420, normal operation mode isbegun. The normal operation mode may include passing the gaseous feedstream is passed to the adsorbent bed units for the swing adsorptionprocess to remove contaminants and pass the product stream to thedownstream process. Then, the downstream process may pass the productstream through the various downstream equipment to produce a finalproduct stream. The downstream process may also pass a purge stream tothe swing adsorption process, which may be utilized during theregeneration step to remove contaminants from the adsorbent beds withinthe adsorbent bed units.

As a specific example, the feed stream may be a natural gas stream thatpredominately contains hydrocarbons and the contaminants within theadsorbent bed may be water. During the regeneration step for therespective adsorbent bed unit, the product stream is passed through theadsorbent bed unit and water interacts with the product stream to formthe purge product stream, which includes the product steam and theportion of the water removed from the respective adsorbent bed.

In addition, the product stream from the adsorbent bed units may beutilized in the startup mode process for one or more downstream units,such as a demethanizer or a liquefaction train. As the downstreamprocesses and units are being started, the spent adsorbent bed units maybe regenerated using a portion of the product stream as the purgestream. Alternatively, the portion of the product stream may be heatedand then have the pressure lowered prior to being passed to the otheradsorbent bed unit during its regeneration step. Once the downstreamprocesses begin normal operation mode, the purge stream may be adjustedto be provided from a residue gas stream, a fuel gas stream or othersuitable stream from one of the downstream processes.

In certain embodiments, the product stream may be further conditionedprior to being provided to the subsequent adsorbent bed unit during itsregeneration step, as the purge stream. In particular, the productstream may be subjected to a heating step prior to being passed to thesecond adsorbent bed unit performing its regeneration step. The heatingstep may heat the product stream to a temperature less than 550° F.,less than 500° F., less than 450° F. or less than 350° F., and may bethe gaseous feed stream temperature, greater than 50° F. of the gaseousfeed stream temperature, greater than 100° F. of the gaseous feed streamtemperature or greater than 250° F. of the gaseous feed streamtemperature. For example, the product stream used during the purge stepmay be a temperature in the range between 500° F. and greater than 50°F. of the gaseous feed stream temperature, in the range between 450° F.and the gaseous feed stream temperature, in the range between 450° F.and greater than 100° F. of the gaseous feed stream temperature or 400°F. and greater than 200° F. of the gaseous feed stream temperature. Theheating of the product stream may include passing the stream through aheat exchanger or similar heating unit to increase the temperature ofthe product stream. Further, the product stream may be subjected to adepressurization step prior to being passed to the second adsorbent bedunit performing its regeneration step. The depressurization step, whichmay be prior to the heating step or following the heating step, maylower the pressure of the product stream to a pressure in the range frombetween 0.1 bar absolute (bara) and 100 bara, which is lower than thepressure within the product stream. The pressure may be lowered by atleast 10%, by at least 20% or at least 30% relative to the pressure ofthe product stream exiting the adsorbent bed. The depressurizing of theproduct stream may include passing the stream through an expander orflash separation vessel to lower the pressure of the product stream.

As further enhancements, the operating conditions may be adjusted duringthe recycle startup mode to manage the removal of contaminants from theadsorbent bed units. By way of example, the flow rate may be in a rangebetween 25 and 1000 million standard cubic feet per day (MSCFD) duringnormal operation mode, while the flow rate may be in the range between6.25 and 500 MSCFD for startup mode. The flow rate may be increasedduring subsequent purge steps until normal operation mode flow rates arereached. Also, the pressure range of the product stream may be in apressure range between atmospheric pressure and fifty psi aboveatmospheric pressure. In addition, the temperature of the product streammay be within a temperature range between 20° Celsius (C) aboveatmospheric temperature and 100° Celsius (C) above atmospherictemperature.

In yet other embodiment, the purge product stream may be subject toconditioning steps to recovery the hydrocarbons from the regenerationstep. Then, the conditioned purge product stream may be recycled to theadsorbent bed units as the gaseous feed stream or intermingled with thegaseous feed stream. For example, the purge product stream may be heatedor cooled and then may be subjected to a flash separation to separatethe water from the remaining portion of the purge product stream. Thepurge product stream may be heated to a temperature greater than 250°F., greater than 350° F. or greater than 450° F. In otherconfigurations, the purge product stream is heated to a temperature 5°F. greater than the dew point of the purge product stream; 10° F.greater than the dew point of the purge product stream; or 20° F.greater than the dew point of the purge product stream. By heating thepurge product stream above the dew point, the heated purge productstream may be used in a subsequent process, such as a gas turbine. Inthis manner, the nitrogen may be regenerated and recycled to theadsorbent beds to remove additional water from the adsorbent beds duringa subsequent purge step. In addition, the purge product may be cooled orcompressed to remove contaminants and may be recycled to be at least aportion of the feed stream or to be at least a portion of the productstream. For example, a flash separation may be utilized to removecontaminants.

To support the recycle startup mode process, a configuration of theswing adsorption process may include additional bypass conduits andmanifold to pass the product stream or a portion of the process streamto the other adsorbent bed units during their regeneration step. Theconfiguration may also include one or more heating units that areupstream of the purge manifold and configured to heat the product streamprior to passing through the adsorbent bed units and/or that aredownstream of the purge product manifold and configured to heat thepurge product stream. The heating unit may include a heat exchanger, afurnace, or the like. The configuration may also include one or moredepressurization units configured to lower the pressure of the productstream. The depressurization units may include one or more expandersand/or one or more separation units. The separation units, which may bea flash separation vessel, may be configured to separate one or morecontaminants from the product stream. Further, the configuration mayinclude one or more regeneration units that are configured to purify thepurge product stream to remove contaminants from the purge productstream.

Exemplary embodiments of steps that may be performed in the startup modeprocess are shown in FIG. 5 to FIG. 12. FIG. 5 is an exemplary diagram500 of a startup mode step in accordance with an embodiment of thepresent techniques. In this diagram 500, an adsorbent bed heating stepis shown. In this heating step, a feed stream, which may be a wet gasstream, may be passed via conduit 502 to a heating unit 504. The heatingunit 504 may be configured to heat the feed stream to a temperature lessthan 550° F., less than 500° F., less than 450° F. or less than 350° F.,and may be the gaseous feed stream temperature, greater than 50° F. ofthe gaseous feed stream temperature, greater than 100° F. of the gaseousfeed stream temperature or greater than 250° F. of the gaseous feedstream temperature. For example, the stream used during the purge stepmay be a temperature in the range between 500° F. and 50° F., in therange between 450° F. and 100° F. or 400° F. and 200° F. (e.g., at atemperature higher than the feed stream temperature). Then, the heatedstream may be passed to a depressurization unit 506. Thedepressurization unit 506 may be configured to lower the pressure of theheated stream to a pressure in the range of 0.1 bar absolute (bara) and100 bara, which is lower than the pressure within the stream prior tothe depressurization unit 506 or which may lower the pressure by atleast 10%, by at least 20% or at least 30% relative to the pressure ofthe stream prior to the depressurization unit 506. Then, the resultingpurge stream is passed from the depressurization unit 506 to theadsorbent bed unit 508 as a purge stream. The purge stream may be passedthrough the adsorbent bed unit to remove one or more contaminants fromthe adsorbent bed unit 508 and conducted away via conduit 510 as a purgeproduct stream.

In this diagram 500, the adsorbent bed unit 508 may initially be atequilibrium with ambient conditions. Then, the feed stream is heated toremove contaminants, such as water. The feed stream may also be replacedwith an external feed, such as nitrogen if available.

FIGS. 6A and 6B are exemplary diagrams 600 and 620 associated withanother startup mode step in accordance with an embodiment of thepresent techniques. In the diagram 600 of FIG. 6A, a blowdown step isshown. In this blowdown step, a blowdown stream, which may be a portionof the gas within the adsorbent bed unit 602, may be passed via conduit604 to a flare (not shown). The blowdown step may be utilized to removea large amount of contaminants, such as water, from the adsorbent bedunit 602.

In FIG. 6B, a diagram 620 of a pressure response 626 is shown along aadsorption axis 622 in moles per kilogram (mol/kg) with respect to apressure axis 622 in bars. In this diagram 620, the response 626 showsequilibrium loading as a function of the partial pressure. As pressurein the adsorbent bed is reduced, the partial pressure lowers resultingin a lower loading on the adsorbent material. This results in desorptionof contaminant from the adsorbent bed which may be conducted away toflare.

FIG. 7 is an exemplary diagram 700 associated with yet another startupmode step in accordance with an embodiment of the present techniques. Inthis diagram 700, an external gas purge step is shown. In this externalgas purge step, an external gaseous stream, which may be a predominatelynitrogen stream, may be passed via conduit 702 to a heating unit 704.The heating unit 704 may be configured to heat the external gas streamto a temperature less than 550° F., less than 500° F., less than 450° F.or less than 350° F., and may be the gaseous feed stream temperature,greater than 50° F. of the gaseous feed stream temperature, greater than100° F. of the gaseous feed stream temperature or greater than 250° F.of the gaseous feed stream temperature. For example, the product streamused during the purge step may be a temperature in the range between500° F. and greater than 50° F. of the gaseous feed stream temperature,in the range between 450° F. and the gaseous feed stream temperature, inthe range between 450° F. and greater than 100° F. of the gaseous feedstream temperature or 400° F. and greater than 200° F. of the gaseousfeed stream temperature. Then, the heated external gas stream may bepassed to the adsorbent bed unit 706 as a heated purge stream. Theheated purge stream may be passed through the adsorbent bed unit 706 toremove one or more contaminants from the adsorbent bed unit 706 andconducted away via conduit 708 as a purge product stream. The purgeproduct stream may be subjected to conditioning and/or flared.

FIG. 8 is an exemplary diagram 800 associated with the recycle startupmode step in accordance with an embodiment of the present techniques. Inthis diagram 800, two adsorbent bed units are shown performing differentsteps in the respective startup mode sequence. The first adsorbent bedunit 802 may be performing an adsorption step, while the secondadsorbent bed unit 804 may be performing a regeneration step (e.g., apurge step). In the adsorption step, a feed stream may be passed viaconduit 806 to first adsorbent bed unit 802. The feed stream mayinteract with the adsorbent bed within the adsorbent bed unit 802 toremove one or more contaminants from the feed stream and the resultingstream may be conducted away via a conduit to a heating unit 808. Theheating unit 808 may be configured to heat the product stream to atemperature of less than 550° F., less than 500° F., less than 450° F.or less than 350° F., and may be the gaseous feed stream temperature,greater than 50° F. of the gaseous feed stream temperature, greater than100° F. of the gaseous feed stream temperature or greater than 250° F.of the gaseous feed stream temperature. For example, the product streamused during the purge step may be a temperature in the range between500° F. and greater than 50° F. of the gaseous feed stream temperature,in the range between 450° F. and the gaseous feed stream temperature, inthe range between 450° F. and greater than 100° F. of the gaseous feedstream temperature or 400° F. and greater than 200° F. of the gaseousfeed stream temperature. Then, the heated product stream may be passedto a depressurization unit 810. The depressurization unit 810 may beconfigured to lower the pressure of the heated product stream to apressure in the range between 0.1 bar absolute (bara) and 100 bara,which is lower than the pressure within the stream prior to thedepressurization unit 810 or which may lower the pressure by at least10%, by at least 20% or at least 30% relative to the pressure of thestream prior to the depressurization unit 810. Then, the resultingstream is passed from the depressurization unit 810 to the secondadsorbent bed unit 804 as a purge stream during the regeneration stepfor the second adsorbent bed unit 804. The purge stream may be passedthrough the second adsorbent bed unit 804 to remove one or morecontaminants from the adsorbent bed within the second adsorbent bed unit804 and conducted away via conduit 812 as a purge product stream. Thepurge product stream may be intermingled with a fuel stream, subject toadditional conditioning and/or flared.

Beneficially, in this recycle startup mode step, the feed to the processis utilized to condition the adsorbent bed units within the process,which is a self-supporting conditioning process for the adsorbent bedunits within the swing adsorption process. This process may continueuntil the product stream satisfies the predetermined specification forthe downstream process. Further, another enhancement the cycle timing,flow rates, pressures and temperatures may be adjusted as necessary forthe process.

FIGS. 9A and 9B are exemplary diagrams 900 and 920 associated with therecycle startup mode step in accordance with an embodiment of thepresent techniques. These diagrams are associated with the configurationfrom FIG. 8. In FIG. 9A, a diagram 900 of a contaminant response 908 isshown along a contaminant axis 902 in parts per million (ppm) withrespect to a cycle axis 904 representing the number of cycles performed.In this diagram 900, the contaminant response 908 continues to decreasefor each cycle performed with the adsorbent bed units, which are shownby the different dots that form the contaminant response 908. Thespecification or predetermined threshold 906 is shown as being set at0.1 ppm. The process using this startup mode sequence reaches thespecification at the 10th cycle. This diagram 900 shows theconcentration of water in the product stream after each subsequentcycle.

In FIG. 9B, a diagram 920 of contaminant adsorption responses 930, 931,932, 933, 934, 935, 936, 937 and 938 is shown along an adsorption axis922 in mol/kg with respect to an axial position in bed axis 924, whichis a normalized location represent by the axial position divided by thelength of the adsorbent bed. In this diagram 920, the response 930 isfor the before the cycles begin, response 931 is for the first cycle,response 932 is for the second cycle, response 933 is for the fourthcycle, response 934 is for the sixth cycle, response 935 is for theeighth cycle, response 936 is for the tenth cycle, response 937 is forthe twelfth cycle and response 938 is for the fourteenth cycle. Thecontaminant adsorption responses 930, 931, 932, 933, 934, 935, 936, 937and 938 continues to decrease for each cycle performed with theadsorbent bed units. This diagram 920 shows the adsorbent loading as afunction of position in the adsorbent bed. Initially, the whole bed isin equilibrium with the ambient conditions. After the first cycle, theproduct end of the bed starts to become dehydrated. By the 10th cycle, adesired adsorbent bed profile has been reached where the resultingproduct stream is at specification.

FIG. 10 is an exemplary diagram 1000 associated with another startupmode step in accordance with an embodiment of the present techniques. Inthis diagram 1000, two adsorbent bed units 1002 and 1004 are shownperforming different steps in the respective recycle startup modesequence after the product stream has reached a level that satisfies thepredetermined threshold. This step would be performed in one or morecycles following performance of the cycles in FIG. 8 and may be used tostartup the downstream processes, such as an NGL system. The firstadsorbent bed unit 1002 may be performing an adsorption step, while thesecond adsorbent bed unit 1004 may be performing a regeneration step(e.g., a purge step). In the adsorption step, a feed stream may bepassed via conduit 1006 to first adsorbent bed unit 1002. The feedstream may interact with the adsorbent bed within the first adsorbentbed unit 1002 to remove one or more contaminants from the feed streamand the resulting stream may be conducted away via a conduit to asplitter 1008. The splitter 1008 may pass a first portion of the productstream to a downstream process via conduit 1010 and may pass a secondportion of the product stream to a heating unit 1012 via conduit 1014.The splitter may be an adjustable valve or group of valves. The heatingunit 1012 may be configured to heat the second portion of the productstream to a temperature greater than 250° F., greater than 350° F. orgreater than 450° F. Then, the heated stream may be passed to adepressurization unit 1016. The depressurization unit 1016 may beconfigured to lower the pressure of the heated stream to a pressure inthe range between 0.1 bar absolute (bara) and 100 bara, which is lowerthan the pressure within the stream prior to the depressurization unit1016 or which may lower the pressure by at least 10%, by at least 20% orat least 30% relative to the pressure of the stream prior to thedepressurization unit 1016. Then, the resulting stream is passed fromthe depressurization unit 1016 to the second adsorbent bed unit 1004 asa purge stream during the regeneration step for the second adsorbent bedunit 1004. The purge stream may be passed through the second adsorbentbed unit 1004 to remove one or more contaminants from the adsorbent bedwithin the second adsorbent bed unit 1004 and conducted away via conduit1018 as a purge product stream. The purge product stream may beintermingled with a fuel stream, subject to additional conditioningand/or flared.

FIG. 11 is an exemplary diagram 1100 associated with still anotherstartup mode step in accordance with an embodiment of the presenttechniques. In this diagram 1100, two adsorbent bed units 1002 and 1004are shown performing different steps in the respective recycle startupmode sequence after the product stream has reached a level thatsatisfies the predetermined threshold and after the downstream processis providing a purge stream to the adsorbent bed units 1002 and 1004.This step may be performed in one or more cycles following performanceof the cycles in FIG. 10, which may include similar reference numbers toFIG. 10, and may be used to transition to normal operation for the swingadsorption process and/or the downstream processes. In thisconfiguration, the splitter 1008 may be adjusted to increase the firstportion of the product stream being provided to the downstream processvia conduit 1010 and may lessen the second portion of the product streambeing provided to the heating unit 1012 via conduit 1014 and thedepressurization unit 1016. The adjustment may be based on the volume ofoverhead stream being provided from the downstream process via conduit1102. The adjustment may include using a valve and/or control system ina cascaded configuration, adjusting the flow rate with a valve orblocking flow with one or more valves. This process may be utilized totransition the swing adsorption process from a RCTSA process to a RCPSAprocess. Also, this process may be used for the startup of an NGLprocess and/or LNG process.

FIG. 12 is an exemplary diagram 1200 associated with normal operationmode. In this diagram 1200, two adsorbent bed units 1202 and 1204 areshown performing different steps in the respective normal operation modesequence after the startup mode is complete. The first adsorbent bedunit 1202 may be performing an adsorption step, while the secondadsorbent bed unit 1204 may be performing a regeneration step (e.g., apurge step). In the adsorption step, a feed stream may be passed viaconduit 1206 to first adsorbent bed unit 1202. The feed stream mayinteract with the adsorbent bed within the first adsorbent bed unit 1202to remove one or more contaminants from the feed stream and theresulting stream may be conducted away via a conduit 1208 to adownstream process. For the regeneration step, the purge stream ispassed via conduit 1210 from the downstream process to the secondadsorbent bed unit 1204. The purge stream may be passed through thesecond adsorbent bed unit 1204 to remove one or more contaminants fromthe adsorbent bed within the second adsorbent bed unit 1204 andconducted away via conduit 1212 as a purge product stream. The purgeproduct stream may be intermingled with a fuel stream, provided to aresidue gas compressor or other additional conditioning process.

As may be appreciated, the startup mode process may include variouscombination of steps to perform the startup mode process. The startupmodes may be integrated together to form an integrated startup mode. Forexample, the startup process may utilize the external startup modesequence for some initial cycles, then may transition to the recyclestartup mode sequence. Further, the startup mode step of FIG. 8 may beutilized after the startup mode step of FIG. 7 and/or after the startupmode step of FIG. 3.

In one or more embodiments, the material may include an adsorbentmaterial supported on a non-adsorbent support. The adsorbent materialsmay include alumina, microporous zeolites, carbons, cationic zeolites,high silica zeolites, highly siliceous ordered mesoporous materials, solgel materials, aluminum phosphorous and oxygen (ALPO) materials(microporous and mesoporous materials containing predominantly aluminumphosphorous and oxygen), silicon aluminum phosphorous and oxygen (SAPO)materials (microporous and mesoporous materials containing predominantlysilicon aluminum phosphorous and oxygen), metal organic framework (MOF)materials (microporous and mesoporous materials comprised of a metalorganic framework) and zeolitic imidazolate frameworks (ZIF) materials(microporous and mesoporous materials comprised of zeolitic imidazolateframeworks). Other materials include microporous and mesoporous sorbentsfunctionalized with functional groups. Examples of functional groupsinclude primary, secondary, tertiary amines and other non protogenicbasic groups such as amidines, guanidines and biguanides.

In one or more embodiments, the adsorbent bed unit may be utilized toseparate contaminants from a feed stream during normal operation mode.The method may include passing a gaseous feed stream at a feed pressurethrough an adsorbent bed unit having an adsorbent contactor to separateone or more contaminants from the gaseous feed stream to form a productstream, wherein the adsorbent contactor has a first portion and a secondportion; interrupting the flow of the gaseous feed stream; performing adepressurization step, wherein the depressurization step reduces thepressure within the adsorbent bed unit; performing an optional heatingstep, wherein the heating step increases the temperature of theadsorbent bed unit to form a temperature differential between the feedend of the adsorbent bed and the product end of the adsorbent bed; andperforming a purge step, wherein the purge step reduces the pressurewithin the adsorbent bed unit; performing a re-pressurization step,wherein the re-pressurization step increases the pressure within theadsorbent bed unit; and repeating the steps a) to e) for at least oneadditional cycle.

Further, in one or more embodiments, the adsorbent bed unit may includean adsorbent bed that can be used for the separation of a target gasform a gaseous mixture. The adsorbent is usually comprised of anadsorbent material supported on a non-adsorbent support, or contactor.Such contactors contain substantially parallel flow channels wherein 20volume percent, preferably 15 volume percent or less of the open porevolume of the contactor, excluding the flow channels, is in poresgreater than about 20 angstroms. A flow channel is taken to be thatportion of the contactor in which gas flows, if a steady state pressuredifference is applied between the point or place at which a feed streamenters the contactor and the point or place at which a product streamleaves the contactor. In the contactor, the adsorbent is incorporatedinto the wall of the flow channel.

In one or more embodiments, when using RCTSA or an integrated RCPSA andRCTSA process, the total cycle times for normal operation mode aretypically less than 600 seconds, preferably less than 400 seconds,preferably less than 300 seconds, preferably less than 250 seconds,preferably less than 180 seconds, more preferably less than 90 seconds,and even more preferably less than 60 seconds. In other embodiment, therapid cycle configuration may be operated at lower flow rates duringstartup mode as compared to normal operation mode, which may result inthe cycle durations being longer than the cycle durations during normaloperation mode. For example, the startup mode cycle duration may be fora period greater than 1 second and less than 2400 seconds, for a periodgreater than 1 second and less than 1500 seconds, for a period greaterthan 1 second and less than 1000 seconds, for a period greater than 1second and less than 600 seconds, for a period greater than 2 second andless than 800 seconds, for a period greater than 2 second and less than400 seconds, for a period greater than 5 second and less than 150seconds or for a period greater than 5 second and less than 90 seconds.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrative embodiments are only preferred examples of the inventionand should not be taken as limiting the scope of the invention.

What is claimed is:
 1. A cyclical swing adsorption system comprising: aplurality of manifolds, wherein the plurality of manifolds comprise afeed manifold configured to pass a feed stream to the plurality ofadsorbent bed units during an adsorption step, a product manifoldconfigured to pass a product stream from the plurality of adsorbent bedunits during the adsorption step, a purge manifold configured to pass apurge stream to the plurality of adsorbent bed units during aregeneration step, a purge product manifold configured to pass a purgeproduct stream from the plurality of adsorbent bed units during theregeneration step, each manifold of the plurality of manifolds isassociated with one swing adsorption process step of a plurality ofswing adsorption process steps; a plurality of adsorbent bed unitscoupled to the plurality of manifolds, each of the adsorbent bed unitscomprising: a housing; an adsorbent material disposed within thehousing; a plurality of valves, wherein at least one of the plurality ofvalves is associated with one of the plurality of manifolds and isconfigured to manage fluid flow along a flow path extending between therespective manifold and the adsorbent material; a startup mode bypassvalve in fluid communication with purge manifold and the productmanifold and configured to provide a flow passage between the productmanifold and the purge manifold in a startup mode position andconfigured to block the flow passage between the product manifold andthe purge manifold in a normal operation mode position.
 2. The cyclicalswing adsorption system of claim 1, wherein the plurality of valvescomprise one or more poppet valves.
 3. The cyclical swing adsorptionsystem of claim 1, wherein the plurality of adsorbent bed units areconfigured to operate at pressures between 0.1 bar absolute (bara) and100 bara.
 4. The cyclical swing adsorption system of claim 1, furthercomprising a heating unit disposed upstream of the purge manifold anddownstream of the product manifold, wherein the heating unit isconfigured to heat the product stream to a temperature in the rangebetween 450° F. and the gaseous feed stream temperature.
 5. The cyclicalswing adsorption system of claim 4, further comprising a separating unitdisposed upstream of the purge manifold and downstream of the heatingunit, wherein the separating unit is configured to lessen the pressureof the product stream by at least 10% as compared to the pressure of theproduct stream upstream of the separating unit.
 6. The cyclical swingadsorption system of claim 1, further comprising a heating unitconfigured to heat the purge product stream to a temperature 10° F.greater than the dew point of the purge product stream.
 7. The cyclicalswing adsorption system of claim 1, further comprising a conditioningunit disposed downstream of the purge product manifold and upstream ofthe feed manifold, wherein the conditioning unit is configured to removeone or more contaminants from the purge product stream.
 8. The cyclicalswing adsorption system of claim 1, wherein the plurality of manifoldsfurther comprise a blowdown manifold configured to pass a blowdownstream from the plurality of adsorbent bed units during a blowdown step.9. The cyclical swing adsorption system of claim 1, further comprising aliquefied natural gas process unit in fluid communication with theadsorbent bed unit and configured to receive the product stream andseparate the product stream into a final product stream and a flash fuelstream, wherein the flash fuel stream is passed to the purge manifold.10. The cyclical swing adsorption system of claim 1, further comprisinga cryogenic natural gas liquid recovery (NGL) process unit in fluidcommunication with the adsorbent bed unit and configured to receive theproduct stream and separate the product stream into a final productstream and a residue gas stream, wherein the residue gas stream ispassed to the purge manifold.
 11. The cyclical swing adsorption systemof claim 10, configured to adjust the amount of the residue gas streamto the purge manifold.
 12. The cyclical swing adsorption system of claim1, further comprising a cryogenic natural gas liquid recovery (NGL)process unit in fluid communication with the adsorbent bed unit whereinthe natural gas liquid recovery (NGL) process unit comprises ademethanizer and a residue gas compressor, and is configured for theresidue gas compressor to recycle a demethanizer column overhead productstream to the mix with a feed stream in the feed manifold.
 13. Thecyclical swing adsorption system of claim 1, configured to pass thepurge product stream to the suction of a residue gas compressor andcombine the purge product stream with the feed stream either upstream ordownstream of a triethylene glycol (TEG) based dehydration unit beforepassing the feed stream to the feed manifold.
 14. The cyclical swingadsorption system of claim 1, configured to heat the plurality ofadsorbent bed units to obtain a temperature differential between thefeed ends of the plurality of adsorbent beds and the product ends of theplurality of adsorbent beds.
 15. The cyclical swing adsorption system ofclaim 1, configured to operate on a cycle duration of greater than 2seconds and less than 800 seconds.